class_name Ball
extends RigidBody3D

# Physics ball. Floor gravity is untouched (gravity_scale in ball.tscn); this
# only adds the wall/ceiling "surface pull" (see ArenaBoundary.get_surface_pull)
# so the ball can cling near a wall for dribbling or hang against the ceiling
# for ceiling shots, plus a safety speed clamp (the ball previously had none).

@export_group("Surface Pull")
@export var wall_pull_strength = 4.0     # Weaker than the ship's — assist, not adherence
@export var wall_pull_range = 2.0
@export var ceiling_pull_strength = 5.5  # Stays below the ball's effective gravity (0.8 * 9.8)
@export var ceiling_pull_range = 2.0

# Kept close to ship_observations.gd's BALL_SPEED_SCALE (30.0) so this feature
# doesn't push ball velocity further out of the range trained policies expect.
const MAX_SPEED := 32.0

var _boundary: ArenaBoundary


func _ready() -> void:
	_boundary = get_tree().get_first_node_in_group("arena_boundary")


func _integrate_forces(state: PhysicsDirectBodyState3D) -> void:
	if _boundary:
		var pull := _boundary.get_surface_pull(
			global_position, wall_pull_strength, wall_pull_range,
			ceiling_pull_strength, ceiling_pull_range
		)
		state.apply_central_force(pull * mass)

	if state.linear_velocity.length() > MAX_SPEED:
		state.linear_velocity = state.linear_velocity.normalized() * MAX_SPEED